package com.itheima.filter;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/*
检查登陆
*/
@WebFilter(value = {"/addStudent.jsp","/listStudentServlet"})
public class LoginFilter implements Filter {
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        //1.将请求和响应对象转换为和HTTP协议相关
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;


        Object username = request.getSession().getAttribute("username");

        //3.判断用户名
        if(username == null || "".equals(username)) {
            //重定向到登录页面
            response.sendRedirect(request.getContextPath() + "/login.jsp");
            return;
        }

        //4.放行
        filterChain.doFilter(request,response);

    }
}
